The official countdown to kickoff might still have over 25 days on it, but close followers of the USC football team know that the season really begins Saturday.

USC takes the practice field for the first time this fall at 4 p.m., and the Trojans are ready to get things rolling.

While parts of camp will be used for installing pieces of the USC game plan for the opener, the bulk of camp will be devoted to "gathering information," as Pete Carroll calls it.

With that in mind, here are some of the areas that will get Carroll's closest attention.

Quarterbacks

Carroll will be wondering if Matt Barkley deserves to be the starting quarterback against San Jose State in the first game of his collegiate career.

Just let that settle for a second.

Could USC actually start a true freshman at quarterback? Yes, if the circumstances are right. Over the summer, it was tough to tell if Barkley closed the gap between him and starter Aaron Corp. But it was clear that Barkley widened the gab between him and Mitch Mustain.

Here are the two scenarios that put Barkley on the start of the field at the beginning of the season.

One, Corp could get injured. With his running style, all it could take would be one wrong plant of the foot and a sprained ankle could mean Barkley at the top of the depth chart.

The second scenario seems more unlikely. If Corp were to become the opposite player that he was during the spring, Barkley could win the job. This means Corp would have to become reckless with the football, turning it over on a regular basis. If Barkley shows he can keep the ball with the offense and Corp falters, the true freshman could be leading the offense in the opener.

While Carroll always favors giving first-team reps to the newbies, it'll be especially important at linebacker. For the entire season, USC will always be one injury away from some major trouble at linebacker because of the lack of depth.

Moving Shane Horton to linebacker helps, but Carroll still needs to watch out for the guys at the top of the order.

The other guys in sweatshirts

Carroll will be wondering just how things are going with his very new staff. He's seen how John Morton and Rocky Seto handled their coordinator duties in the spring. Now, it's time for those two to handle the build up to an actual game.

Carroll saw Jeremy Bates calling plays this spring, but now it's time to see if he can put together a collegiate game plan.